Electrical power distribution grids use electrical components, such as transformers, capacitors, and reactors. Potentially dangerous conditions can be created in such devices when aging or operating stresses cause the insulation system to fail. A short circuit within such a device can release a large amount of energy within a fraction of a second. In the worst case the device can explode due to rapid internal pressure buildup from the vaporization of insulating oil and the decomposition of the oil vapor into combustible or volatile gases.
It is known that there is a transient or rapid surge in pressure inside oil-filled electrical devices, such as transformers or voltage regulators, when the devices suffer from an internal arcing fault. This happens because arcing produces a marked increase in temperature which vaporizes some of the oil. Some electrical devices are filled with electrically insulating gases such as SF6. Devices for detecting such rapid pressure surges, and for indicating that such rapid pressure surges have occurred within an electrical device, are known, for example as described in U.S. Pat. Nos. 6,812,713, 6,429,662, 5,078,078, and Patent Cooperation Treaty publication No. WO 2011/153604, all of which are hereby incorporated by reference herein. Such devices may also include a pressure relief valve for relieving a buildup of pressure within the electrical device during normal operation.
Higher operating temperatures in electrical devices can indicate that the electrical device is not sufficiently robust to perform the job for which it has been deployed. Thus, information about the temperature at which an electrical device is operating can provide useful information regarding the appropriateness of that electrical device to its current operating location.
Devices such as pressure relief valves may be used to vent increases in pressure within an electrical device during a range of normal operating conditions. It may be desirable for an operator to know that a pressure relief valve has been actuated on a device.
It may be desirable to provide rapid venting (i.e. to an extent beyond that provided by a conventional pressure relief valve) of an electrical device, in the event that there is a sudden buildup of pressure within the device.
The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.